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zsh/Src/compat.c

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/*
* compat.c - compatibility routines for the deprived
*
* This file is part of zsh, the Z shell.
*
* Copyright (c) 1992-1997 Paul Falstad
* All rights reserved.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and to distribute modified versions of this software for any
* purpose, provided that the above copyright notice and the following
* two paragraphs appear in all copies of this software.
*
* In no event shall Paul Falstad or the Zsh Development Group be liable
* to any party for direct, indirect, special, incidental, or consequential
* damages arising out of the use of this software and its documentation,
* even if Paul Falstad and the Zsh Development Group have been advised of
* the possibility of such damage.
*
* Paul Falstad and the Zsh Development Group specifically disclaim any
* warranties, including, but not limited to, the implied warranties of
* merchantability and fitness for a particular purpose. The software
* provided hereunder is on an "as is" basis, and Paul Falstad and the
* Zsh Development Group have no obligation to provide maintenance,
* support, updates, enhancements, or modifications.
*
*/
#include "zsh.mdh"
#include "compat.pro"
/* Return pointer to first occurence of string t *
* in string s. Return NULL if not present. */
#ifndef HAVE_STRSTR
char *
strstr(const char *s, const char *t)
{
char *p1, *p2;
for (; *s; s++) {
for (p1 = s, p2 = t; *p2; p1++, p2++)
if (*p1 != *p2)
break;
if (!*p2)
return (char *)s;
}
return NULL;
}
#endif
#ifndef HAVE_GETHOSTNAME
int
gethostname(char *name, size_t namelen)
{
struct utsname uts;
uname(&uts);
if(strlen(uts.nodename) >= namelen) {
errno = EINVAL;
return -1;
}
strcpy(name, uts.nodename);
return 0;
}
#endif
#ifndef HAVE_GETTIMEOFDAY
int
gettimeofday(struct timeval *tv, struct timezone *tz)
{
tv->tv_usec = 0;
tv->tv_sec = (long)time((time_t) 0);
return 0;
}
#endif
/* compute the difference between two calendar times */
#ifndef HAVE_DIFFTIME
double
difftime(time_t t2, time_t t1)
{
return ((double)t2 - (double)t1);
}
#endif
#ifndef HAVE_STRERROR
extern char *sys_errlist[];
/* Get error message string associated with a particular *
* error number, and returns a pointer to that string. *
* This is not a particularly robust version of strerror. */
char *
strerror(int errnum)
{
return (sys_errlist[errnum]);
}
#endif
#if 0
/* pathconf(_PC_PATH_MAX) is not currently useful to zsh. The value *
* returned varies depending on a number of factors, e.g. the amount *
* of memory available to the operating system at a given time; thus *
* it can't be used for buffer allocation, or even as an indication *
* of whether an attempt to use or create a given pathname may fail *
* at any future time. *
* *
* The call is also permitted to fail if the argument path is not an *
* existing directory, so even to make sense of that one must search *
* for a valid directory somewhere in the path and adjust. Even if *
* it succeeds, the return value is relative to the input directory, *
* and therefore potentially relative to the length of the shortest *
* path either to that directory or to our working directory. *
* *
* Finally, see the note below for glibc; detection of pathconf() is *
* not by itself an indication that it works reliably. */
/* The documentation for pathconf() says something like: *
* The limit is returned, if one exists. If the system does *
* not have a limit for the requested resource, -1 is *
* returned, and errno is unchanged. If there is an error, *
* -1 is returned, and errno is set to reflect the nature of *
* the error. *
* *
* System calls are not permitted to set errno to 0; but we must (or *
* some other flag value) in order to determine that the resource is *
* unlimited. What use is leaving errno unchanged? Instead, define *
* a wrapper that resets errno to 0 and returns 0 for "the system *
* does not have a limit," so that -1 always means a real error. */
/**/
mod_export long
zpathmax(char *dir)
{
#ifdef HAVE_PATHCONF
long pathmax;
errno = 0;
if ((pathmax = pathconf(dir, _PC_PATH_MAX)) >= 0) {
/* Some versions of glibc pathconf return a hardwired value! */
return pathmax;
} else if (errno == EINVAL || errno == ENOENT || errno == ENOTDIR) {
/* Work backward to find a directory, until we run out of path. */
char *tail = strrchr(dir, '/');
while (tail > dir && tail[-1] == '/')
--tail;
if (tail > dir) {
*tail = 0;
pathmax = zpathmax(dir);
*tail = '/';
} else {
errno = 0;
if (tail)
pathmax = pathconf("/", _PC_PATH_MAX);
else
pathmax = pathconf(".", _PC_PATH_MAX);
}
if (pathmax > 0) {
long taillen = (tail ? strlen(tail) : (strlen(dir) + 1));
if (taillen < pathmax)
return pathmax - taillen;
else
errno = ENAMETOOLONG;
}
}
if (errno)
return -1;
else
return 0; /* pathmax should be considered unlimited */
#else
long dirlen = strlen(dir);
/* The following is wrong if dir is not an absolute path. */
return ((long) ((dirlen >= PATH_MAX) ?
((errno = ENAMETOOLONG), -1) :
((errno = 0), PATH_MAX - dirlen)));
#endif
}
#endif /* 0 */
#ifdef HAVE_SYSCONF
/* This is replaced by a macro from system.h if not HAVE_SYSCONF. *
* 0 is returned by sysconf if _SC_OPEN_MAX is unavailable; *
* -1 is returned on error *
* *
* Neither of these should happen, but resort to OPEN_MAX rather *
* than return 0 or -1 just in case. */
/**/
mod_export long
zopenmax(void)
{
static long openmax = 0;
if (openmax < 1) {
if ((openmax = sysconf(_SC_OPEN_MAX)) < 1) {
openmax = OPEN_MAX;
} else if (openmax > OPEN_MAX) {
/* On some systems, "limit descriptors unlimited" or the *
* equivalent will set openmax to a huge number. Unless *
* there actually is a file descriptor > OPEN_MAX already *
* open, nothing in zsh requires the true maximum, and in *
* fact it causes inefficiency elsewhere if we report it. *
* So, report the maximum of OPEN_MAX or the largest open *
* descriptor (is there a better way to find that?). */
long i, j = OPEN_MAX;
for (i = j; i < openmax; i += (errno != EINTR)) {
errno = 0;
if (fcntl(i, F_GETFL, 0) < 0 &&
(errno == EBADF || errno == EINTR))
continue;
j = i;
}
openmax = j;
}
}
return (max_zsh_fd > openmax) ? max_zsh_fd : openmax;
}
#endif
/**/
mod_export char *
zgetdir(struct dirsav *d)
{
char nbuf[PATH_MAX+3];
char *buf;
int bufsiz, pos;
struct stat sbuf;
ino_t pino;
dev_t pdev;
#if !defined(__CYGWIN__) && !defined(USE_GETCWD)
struct dirent *de;
DIR *dir;
dev_t dev;
ino_t ino;
int len;
#endif
buf = zhalloc(bufsiz = PATH_MAX);
pos = bufsiz - 1;
buf[pos] = '\0';
strcpy(nbuf, "../");
if (stat(".", &sbuf) < 0) {
if (d)
return NULL;
buf[0] = '.';
buf[1] = '\0';
return buf;
}
pino = sbuf.st_ino;
pdev = sbuf.st_dev;
if (d)
d->ino = pino, d->dev = pdev;
#ifdef HAVE_FCHDIR
else
#endif
#if !defined(__CYGWIN__) && !defined(USE_GETCWD)
holdintr();
for (;;) {
if (stat("..", &sbuf) < 0)
break;
ino = pino;
dev = pdev;
pino = sbuf.st_ino;
pdev = sbuf.st_dev;
if (ino == pino && dev == pdev) {
if (!buf[pos])
buf[--pos] = '/';
if (d) {
#ifndef HAVE_FCHDIR
zchdir(buf + pos);
noholdintr();
#endif
return d->dirname = ztrdup(buf + pos);
}
zchdir(buf + pos);
noholdintr();
return buf + pos;
}
if (!(dir = opendir("..")))
break;
while ((de = readdir(dir))) {
char *fn = de->d_name;
/* Ignore `.' and `..'. */
if (fn[0] == '.' &&
(fn[1] == '\0' ||
(fn[1] == '.' && fn[2] == '\0')))
continue;
#ifdef HAVE_STRUCT_DIRENT_D_STAT
if(de->d_stat.st_dev == dev && de->d_stat.st_ino == ino) {
strncpy(nbuf + 3, fn, PATH_MAX);
break;
}
#else /* !HAVE_STRUCT_DIRENT_D_STAT */
# ifdef HAVE_STRUCT_DIRENT_D_INO
if (dev != pdev || (ino_t) de->d_ino == ino)
# endif /* HAVE_STRUCT_DIRENT_D_INO */
{
strncpy(nbuf + 3, fn, PATH_MAX);
lstat(nbuf, &sbuf);
if (sbuf.st_dev == dev && sbuf.st_ino == ino)
break;
}
#endif /* !HAVE_STRUCT_DIRENT_D_STAT */
}
closedir(dir);
if (!de)
break;
len = strlen(nbuf + 2);
pos -= len;
while (pos <= 1) {
char *newbuf = zhalloc(2*bufsiz);
memcpy(newbuf + bufsiz, buf, bufsiz);
buf = newbuf;
pos += bufsiz;
bufsiz *= 2;
}
memcpy(buf + pos, nbuf + 2, len);
#ifdef HAVE_FCHDIR
if (d)
return d->dirname = ztrdup(buf + pos + 1);
#endif
if (chdir(".."))
break;
}
if (d) {
#ifndef HAVE_FCHDIR
if (*buf)
zchdir(buf + pos + 1);
noholdintr();
#endif
return NULL;
}
if (*buf)
zchdir(buf + pos + 1);
noholdintr();
#else /* __CYGWIN__, USE_GETCWD cases */
if (!getcwd(buf, bufsiz)) {
if (d) {
return NULL;
}
} else {
if (d) {
return d->dirname = ztrdup(buf);
}
return buf;
}
#endif
buf[0] = '.';
buf[1] = '\0';
return buf;
}
/**/
char *
zgetcwd(void)
{
return zgetdir(NULL);
}
/* chdir with arbitrary long pathname. Returns 0 on success, -1 on normal *
* failure and -2 when chdir failed and the current directory is lost. */
/**/
mod_export int
zchdir(char *dir)
{
char *s;
int currdir = -2;
for (;;) {
if (!*dir || chdir(dir) == 0) {
#ifdef HAVE_FCHDIR
if (currdir >= 0)
close(currdir);
#endif
return 0;
}
if ((errno != ENAMETOOLONG && errno != ENOMEM) ||
strlen(dir) < PATH_MAX)
break;
for (s = dir + PATH_MAX - 1; s > dir && *s != '/'; s--)
;
if (s == dir)
break;
#ifdef HAVE_FCHDIR
if (currdir == -2)
currdir = open(".", O_RDONLY|O_NOCTTY);
#endif
*s = '\0';
if (chdir(dir) < 0) {
*s = '/';
break;
}
#ifndef HAVE_FCHDIR
currdir = -1;
#endif
*s = '/';
while (*++s == '/')
;
dir = s;
}
#ifdef HAVE_FCHDIR
if (currdir >= 0) {
if (fchdir(currdir) < 0) {
close(currdir);
return -2;
}
close(currdir);
return -1;
}
#endif
return currdir == -2 ? -1 : -2;
}
/*
* How to print out a 64 bit integer. This isn't needed (1) if longs
* are 64 bit, since ordinary %ld will work (2) if we couldn't find a
* 64 bit type anyway.
*/
/**/
#ifdef ZSH_64_BIT_TYPE
/**/
mod_export char *
output64(zlong val)
{
static char llbuf[DIGBUFSIZE];
convbase(llbuf, val, 0);
return llbuf;
}
/**/
#endif /* ZSH_64_BIT_TYPE */
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